So-called Quenching Devices release the explosion via a rupture disc into a filter system. This filter, preferably stainless mesh, retards the flame and contains dust. Explosion pressure and temperatures are reduced to a negligible level outside the device. These explosion traps allow safe venting of Dust Explosions indoors.
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Potential ignition sources which can carry enough energy to start an explosion (acc. EN 1127-1):
- Hot surfaces
- Sparks from electrical equipment
- Electrical equipment and lights
- Stray currents from electrical equipment
- Electrostatic discharge sparks
- Lightning strikes
- Electromagnetic fields in frequencies from 9kHz up to 300GHz
- Electromagnetic radiation in frequencies from 300GHz up to 3 x 106 GHz and of different wavelengths from 1000µm up to 0,1 µm (optical spectral range)
- Ionizing Radiation
- Adiabatic compression, shock wave, running gases
- Chemical reaction
- And not to forget: The human factor which turns all potential ignition sources into effective ones.
Measure to prevent the propagation of an explosion from one building to another (e.g. by using automatically closing fire doors, gas tight seals, explosion doors etc.).
Measures which must be taken to ensure that the plant remains operable and in its design state (e.g. cleaning, oiling and greasing etc.). Maintenance should also include control and evaluation measures to identify any deviations from the intended design of the plant (e.g. Management of Change procedure).
Lowest spark energy from a capacitative circuit which is sufficient to ignite the most ignitable dust | air mixture under defined test conditions.
Filter system which is fitted to the clean side of a main filter to prevent the formation of a dust cloud in downstream equipment (e.g. fan) in the event of filter bag breakage or other failure.